When you specify a default value for an entity attribute, OutSystems uses that when you make a new record and do not/fail to specify the value for that attribute.
However, when you publish your changes, the database is filled with the "blank" value instead of the default value.
To illustrate, if you add a new column called Quantity to multiply an expense by, you give it a default value of 1 so that the value comes out the same. However, the new Quantity column in the database is filled with zeroes
It's not hard to get around - you just have to make update SQL that sets all the zeroes or blanks to the default value - but it seems like it shouldn't be necessary :)
-- Ritchie Annand